package com.ioc;

import java.io.File;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

/**
 * 遍历包下所有类
 */
public class ClassUtil {
    public static void main(String[] args) {
        String packageName="com.ioc"; //填入完整包名
        Set<String> classNames=getClassName(packageName,true);
        if(classNames!=null){
            for (String className:classNames){
                System.out.println(className);
            }
        }
    }

    /**
     * 获取某包下所有类
     * @param packageName 包名
     * @param isRecursion   是否遍历子包
     * @return 类的完整名称
     */
    public static Set<String>getClassName(String packageName,boolean isRecursion){
        Set<String> classNames =null;
        ClassLoader loader=Thread.currentThread().getContextClassLoader();
        String packagePath=packageName.replace(".","/");
        URL url=loader.getResource(packagePath);
        if(url!=null){
            String protocol=url.getProtocol();
            if (protocol.equals("file")){
                classNames=getClassNameFromDir(url.getPath(),packageName,isRecursion);
            }else if (protocol.equals("jar")){
                JarFile jarFile=null;
                try {
                    jarFile=((JarURLConnection)url.openConnection()).getJarFile();
                }catch (Exception e){
                    e.printStackTrace();
                }
                if (jarFile!=null){
                    getClassNameFromJar(jarFile.entries(),packageName,isRecursion);
                }
            }
        }else{
            classNames=getClassNameFromJars(((URLClassLoader)loader).getURLs(),packageName,isRecursion);

        }
        return classNames;
    }
    /**
     * 从项目文件获取某包下�?有类
     *
     * @param filePath    文件路径
     * @param packageName   类名集合
     * @param isRecursion 是否遍历子包
     * @return 类的完整名称
     */

    private static Set<String> getClassNameFromDir(String filePath,String packageName,boolean isRecursion){
        Set<String> className=new HashSet<String>();
        File file=new File(filePath);
        File[] files=file.listFiles();
        for (File childFile :files){
            if (childFile .isDirectory()){
                if(isRecursion){
                    className.addAll(getClassNameFromDir(childFile.getPath(),packageName+ "." + childFile.getName(), isRecursion));

                }
            }else{
                String fileName=childFile.getName();
                //endsWith() 方法用于测试字符串是否以指定的后 结束 fileName.contains("$") 文件名中不包�? '$'
                if (fileName.endsWith(".class") && !fileName.contains("$")) {
                    className.add(packageName + "." + fileName.replace(".class", ""));
                }
            }
        }
        return className;
    }


    /**
     * @param jarEntries
     * @param packageName
     * @param isRecursion
     * @return
     */
    private static Set<String> getClassNameFromJar(Enumeration<JarEntry> jarEntries, String packageName, boolean isRecursion) {
        Set<String> classNames = new HashSet<String>();

        while (jarEntries.hasMoreElements()) {
            JarEntry jarEntry = jarEntries.nextElement();
            if (!jarEntry.isDirectory()) {
                /*
                 * 这里是为了方便，先把"/" 转成 "." 再判�? ".class" 的做法可能会有bug
                 * (FIXME: 先把"/" 转成 "." 再判�? ".class" 的做法可能会有bug)
                 */
                String entryName = jarEntry.getName().replace("/", ".");
                if (entryName.endsWith(".class") && !entryName.contains("$") && entryName.startsWith(packageName)) {
                    entryName = entryName.replace(".class", "");
                    if (isRecursion) {
                        classNames.add(entryName);
                    } else if (!entryName.replace(packageName + ".", "").contains(".")) {
                        classNames.add(entryName);
                    }
                }
            }
        }

        return classNames;
    }

    /**
     * 从所有jar中搜索该包，并获取该包下�?有类
     *
     * @param urls        URL集合
     * @param packageName 包路�?
     * @param isRecursion 是否遍历子包
     * @return 类的完整名称
     */
    private static Set<String> getClassNameFromJars(URL[] urls, String packageName, boolean isRecursion) {
        Set<String> classNames = new HashSet<String>();

        for (int i = 0; i < urls.length; i++) {
            String classPath = urls[i].getPath();

            //不必搜索classes文件�?
            if (classPath.endsWith("classes/")) {
                continue;
            }

            JarFile jarFile = null;
            try {
                jarFile = new JarFile(classPath.substring(classPath.indexOf("/")));
            } catch (IOException e) {
                e.printStackTrace();
            }

            if (jarFile != null) {
                classNames.addAll(getClassNameFromJar(jarFile.entries(), packageName, isRecursion));
            }
        }

        return classNames;
    }

}
